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Abstract: This Letter, describes the complexation of α-, β- and γ-cyclodextrins (1–3) with TTF derivative 4 in water. In particular, we show using 1H, 13C NMR, UV–vis spectroscopy and isothermal titration calorimetry that β-cyclodextrin 2 forms an effective complex with 4. Complex 2·4 can be conveniently disassembled upon the addition of 1-adamantanol. [Copyright &y& Elsevier]

Abstract: We report the convenient synthesis of a pyrrole-functionalized tetracationic cyclophane, [2]rotaxane, and [2]catenane. X-ray crystallography has confirmed the interlocked structure of the catenane. We have investigated the solution properties of these systems using solution electrochemistry, NMR, and UV–vis spectroscopy. We have also demonstrated that it is possible to immobilize these systems onto a platinum working electrode surface. We have shown that films of the cyclophane have the ability to undergo complexation with a dialkyloxynaphthalene derivative. [Copyright &y& Elsevier]

Abstract: This article reports the characterization of pseudorotaxanes fabricated from cyclobis(paraquat-p-phenylene) 1, and 1,4-dialkyloxyphenyl derivative 2 or 1,5-dialkyloxynaphthalene derivative 3 in water. Addition of competing guest 3 to 1.2 or the electrochemical reduction of the cyclophane of 1.3 results in a dethreading of the original pseudorotaxane architecture. [Copyright &y& Elsevier]

Abstract: We report the synthesis of a cyclodextrin-based molecular adapter which has the propensity to form an electrochemically tuneable ternary complex with cyclophanes 2 or 3 and ferrocene 4 in non-aqueous and aqueous environments, respectively. [Copyright &y& Elsevier]

Abstract: We report the application of electrochemistry to detect and modulate hydrogen bonding interactions between a phenanthrenequinone-functionalized self-assembled monolayer and a phenyl-urea terminated dendrimer. [Copyright &y& Elsevier]

Abstract: We report the synthesis of a dithienylpyrrole-stoppered rotaxane and its subsequent electrochemical polymerisation onto a platinum working electrode surface. We have shown that the tetracationic cyclophane moiety of the rotaxane does not impair electropolymerisation of this derivative. Indeed, functionalised films can be conveniently prepared by oxidative polymerisation of the dithienylpyrrole stopper units, to yield a network of rotaxane units interconnected by a conducting polymer backbone. [Copyright &y& Elsevier]

Salt bridge formation between ferrocenecarboxylic acid and an excess of a N,N′-diethylsubstituted benzamidine leads to a -0.27 V shift in the half-wave potential of the ferrocene moiety, corresponding to a 26 kJ mol-1 stabilisation of the ferrocenium state. [Copyright &y& Elsevier]

We describe the electrochemically controlled hydrogen bonding interactions between the isobutyl flavin/2,6-diferrocenylamidopyridine (2·5) and 9,10-phenanthrenequinone/1-ferrocenyl-3-hexylurea (4·6) dyads. Cyclic and square wave voltammetry studies have shown that the binding efficiencies between these moieties can be electrochemically actuated in non-polar (CH2Cl2 for 2·5) or polar (DMF for 4·6) organic solvents between three distinct states. [Copyright &y& Elsevier]

We have investigated the electrochemically controlled hydrogen bonding interactions between tetrathiafulvalene host 3 and guests 4 or 5. Stabilisation of the 3+⋅ state is dependent upon the nature of the guest species, whereas both guests prevent precipitation of the electrochemically generated 32+ species at the working electrode via hydrogen bonded molecular recognition processes. [Copyright &y& Elsevier]

Abstract: The synthesis of a polypseudorotaxane, polyrotaxane, and polycatenane containing the electron-deficient cyclophane cyclobis(paraquat-p-phenylene) (CBPQT4+) subunit in the side chain is described. These interlocked supramolecular polymers have been prepared from an azide-functionalized polystyrene derivative and an acetylene-functionalized [2]rotaxane, [2]catenane and their parent tetracationic cyclophane via Cu(I)-catalyzed 1,3 dipolar cycloadditions (‘click chemistry’). The synthesis and characterization of the polymers and intermediates has been described using IR, 1H NMR, UV spectroscopies, and voltammetry. We have shown that the CBPQT4+ unit of the side chain polystyrene derivative has the ability to reversibly undergo complexation with a complementary dialkoxynaphthalene derivative. [Copyright &y& Elsevier]

The singlet exciton diffusion length was measured in a small molecule electron donor material DR3TBDTT using fluorescence quenching at a planar interface with a cross-linked fullerene derivative. The one-dimensional exciton diffusion length was increased from ~16 to ~24 nm by annealing the film in carbon disulfide solvent vapor. Planar heterojunction solar cells were fabricated using bilayers of these materials and it was found that solvent vapor annealing increased the short circuit current density by 46%. This can be explained by improved exciton harvesting in the annealed bilayer. Image 1 • Exciton diffusion in DR3TBDTT is engineered by solvent vapor annealing. • Bilayer OPV device with well-defined donor-acceptor interface is fabricated for investigating effect of exciton diffusion. • Optical model confirms the significance of exciton diffusion in determining bilayer device efficiency. [ABSTRACT FROM AUTHOR]

Three ‘D-π-A-π-A’ based dyes have been synthesized featuring MeO-, MeS- and Me 2 N- as donor residues and benzothiadiazole and cyanoacrylic acid residues as acceptor units. UV–vis spectroscopy, solution electrochemistry and DFT modelling indicated that the Me 2 N- residue has the most significant effect on optical and redox properties of a photosensitizer. DSSCs with the Me 2 N- functionalized dye gave the highest power conversion efficiency of the series (η = 5.61%), presumably due to the better donor ability of this unit, which promotes more effective intramolecular charge transfer (ICT) characteristics. [ABSTRACT FROM AUTHOR]

We report a multi-stimuli responsive polymeric sensor consisting of a pseudorotaxane-like architecture fabricated from a 1,5-diaminonaphthalene end-functionalized poly( N -isopropyl)acrylamide ( Napht-N-PNIPAM ) and cyclobis(paraquat- p -phenylene) ( CBPQT 4 + , 4Cl − ). The coloured nature of the poly-pseudorotaxane provides a sensor for temperature and pH in water with an associated visible readout. To create this dual responsive polymeric sensor, a new chain transfer agent ( Napht-N-CTA ) incorporating a pH-responsive 1,5-diaminonaphthalene unit was synthesized and used for the polymerization of N -isopropylacrylamide via Reversible Addition-Fragmentation Chain Transfer (RAFT). The ability of Napht-N-PNIPAM to form a pseudorotaxane architecture with CBPQT 4 + , 4Cl − in aqueous media was studied by means of UV–Vis, NMR ( 1 H, 2D-ROESY, DOSY) and ITC experiments. Interestingly, the pseudorotaxane architecture can be reversibly dissociated upon either heating the sample above its cloud point or protonating the nitrogen atoms of the 1,5-diaminonaphthalene-based guest unit by adjusting the pH to around 1. In both cases a dramatic colour change occurs from intense blue-green to colourless. [ABSTRACT FROM AUTHOR]

Abstract: In this article, we report the facile synthesis of metal-free dyes 6 and 7, their solution-based optical and redox properties and their use as sensitizers in dye-sensitized solar cells (DSSCs). Our studies indicate that the addition of the second thiophene unit in dye 7, decreases the oxidation and reduction potential and consequently the band gap of the molecule compared to 6. Furthermore, increasing the length of the conjugated spacer also affects on the properties of the DSSCs, with dye 7 providing a higher power conversion efficiency compared to 6 (η = 4.49 versus 3.23%). [Copyright &y& Elsevier]

Abstract: In this Letter, we describe the formation of complexes between flavin and diamidopyridine functionalized porphyrin systems via hydrogen bonding and π-stacking interactions. [Copyright &y& Elsevier]

Abstract: 1,5-Di(hetero)arylated-pyridin-2(1H)-one derivatives have been readily obtained in good yields starting from 2-fluoro-5-pyridylboronic acid. The sequence comprises three steps: (i) palladium-catalysed Suzuki-Miyaura reaction; (ii) base-catalysed hydrolysis; (iii) copper-catalysed C–N coupling. X-ray crystal structures are reported for selected pyridin-2(1H)-one derivatives. These compounds are of interest as new scaffolds for drug discovery. [Copyright &y& Elsevier]

The ever-increasing demand for renewable energy has led to the intensification of research focused upon harnessing the abundant energy from sunlight. Solution processed organic solar cells fabricated using conjugated polymer donor materials dominated the early development of organic photovoltaics (OPV). More recently, organic solar cells fabricated using small molecule donors have become increasingly attractive due to the advantages these systems have over their polymeric counterparts. These include reproducible synthesis and the ability to more accurately develop structure-activity relationships. Here, we report the synthesis of thiophene based small molecule donors that have been used to investigate the influence of alkyne π-spacers on the optical, electronic and photovoltaic properties of solution-processable bulk-heterojunction (BHJ) organic OPV cells. Additionally, we compare the addition of 3,4-ethylenedioxythiophene (EDOT) units in place of the end-thiophene of these derivatives. We found that the compounds featuring alkyne moieties displayed poor charge transfer and blue-shifted UV–vis spectra, whereas the incorporation of the EDOT units increased charge transfer for the non-alkyne derivative resulting in red-shifted absorbance. DFT calculations predicted higher charge separation/mobility and lower charge generation for the compounds without alkyne units. Indeed, greater J sc values and higher PCEs were found for the compounds lacking alkyne spacers. EDOT containing compounds showed poor performance which is likely due to an unfavourable morphology and higher HOMO level, leading to lower V oc. Hence, the simplest 5T-1 molecule showed the highest performance of 3.24%, which is c.a. 1.6x that of the alkyne-containing 5TA-1 and c.a. 2.9x that of the EDOT-containing derivative. This study demonstrates that alkyne spacers can be detrimental to orbital interactions, charge transfer and OPV performance, and that the EDOT unit can be added to provide greater charge transfer due to its auxiliary donating ability. However, careful design is required to ensure higher V oc values and a favourable morphology in thiophene-based solution-processable OPVs. • The role alkynes play in the photophysics and OPV performance of a series of thiophene-based dyes is investigated. • Alkyne-containing compounds show poorer CT and blue-shifted UV-vis spectra. • Alkyne-free compounds show the highest device performances. • EDOT moieties provide greater CT, however, they lead to unfavourable morphology. [ABSTRACT FROM AUTHOR]

Abstract: In this Letter we report a ferrocene-functionalised polydiacetylene liposome that has the propensity to respond colorimetrically and electrochemically upon binding to a cyclodextrin oligomer. [Copyright &y& Elsevier]